a process whose average over time converges to the true average

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Daily Archives: January 11, 2011

At the end of last week I learned, much to my sadness, that Rudolf Ahlswede passed away in December. There will be some sort of commemoration at the ITA workshop. His Wikipedia entry has been edited, but I couldn’t find an obituary. It does have a rather dashing photograph of him in earlier years. I think the sideburns suited him.

Rudi Ahlswede was one of the pillars of Information Theory and had many seminal works in that field using tools from combinatorics, probability, and graph theory. I came to know his work through my dissertation work on the arbitrarily varying channel (AVCs); he had written extensively on the AVC starting in the 1960s. Of particular note (to me) was his paper on the “elimination technique,” which is one of the first derandomization arguments I’ve seen in the literature. And of course he was part of the start of Network Coding. I met Ahlswede at the 2006 ISIT and then most recently in September at ITW in Dublin, where I was presenting a paper on AVCs in which the adversary has a noisy look at the transmitted codeword. He presented in the same session a paper on “channels with time structure,” about which I will make a separate post later. I just wanted to note with sadness the passing of such a giant.